[Backport 2.x] Command with query parameter reports unrecognized parameter in DevTools

src/plugins/console/server/routes/api/console/proxy/create_handler.ts

@@ -70,13 +70,15 @@ function getProxyHeaders(req: OpenSearchDashboardsRequest) {
 }
 
 function toUrlPath(path: string) {
-  let urlPath = `/${trimStart(path, '/')}`;
+  const FAKE_BASE = 'http://localhost';
+  const urlWithFakeBase = new URL(`${FAKE_BASE}/${trimStart(path, '/')}`);
   // Appending pretty here to have OpenSearch do the JSON formatting, as doing
   // in JS can lead to data loss (7.0 will get munged into 7, thus losing indication of
   // measurement precision)
-  if (!urlPath.includes('?pretty')) {
-    urlPath += '?pretty=true';
+  if (!urlWithFakeBase.searchParams.get('pretty')) {
+    urlWithFakeBase.searchParams.append('pretty', 'true');
   }
+  const urlPath = urlWithFakeBase.href.replace(urlWithFakeBase.origin, '');
   return urlPath;
 }
 

src/plugins/console/server/routes/api/console/proxy/tests/query_string.test.ts

@@ -82,6 +82,14 @@ describe('Console Proxy Route', () => {
           expect(args.path).toBe('/index/id?pretty=true');
         });
       });
+
+      describe(`contains query parameter`, () => {
+        it('adds slash to path before sending request', async () => {
+          await request('GET', '_cat/tasks?v');
+          const [[args]] = opensearchClient.asCurrentUser.transport.request.mock.calls;
+          expect(args.path).toBe('/_cat/tasks?v=&pretty=true');
+        });
+      });
     });
   });
 });